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HTTP 505 HTTP Version Not Supported

The server does not support the HTTP protocol version used in the request.

5xx · Server error✗ not retryable — fix the request instead

Fix checklist

  • Let your HTTP client negotiate the version automatically.
  • Remove forced HTTP/2-prior-knowledge settings against servers that lack it.

Spec: RFC reference

Related status codes

500 Internal Server Error

The server hit an unexpected condition.

501 Not Implemented

The server does not support the functionality required to fulfil the request..

502 Bad Gateway

A gateway or proxy received an invalid response from the upstream server..

503 Service Unavailable

The server is temporarily unable to handle the request — overload or maintenance.

← All HTTP status codes